It could be a rogue Sith Lord who has broken away from the traditional Sith teachings and is causing destruction in his own way. He might not be interested in the age - old battle between the Sith and the Jedi but just wants to spread chaos for his own reasons.
A powerful, corrupt politician could be the main antagonist. Using their political power and influence, they manipulate events and start wars, leading to a path of destruction. They might be secretly in league with criminal organizations or have their own hidden agenda that benefits only them and a select few, all while the galaxy suffers.
The main character is Darth Bane, of course. He is a Sith Lord on a path of self - discovery and power - seeking. Another important character is his master, who initially trains him in the ways of the Sith. And there are also some Jedi characters who cross paths with Darth Bane and oppose his actions.
Perhaps an ancient evil force that Darth Vectivus accidentally awakens. This force is much more powerful than him and starts to control him, making him do things he doesn't really want to. Now Darth Vectivus has to find a way to break free from this new master while also dealing with the rest of the galaxy that sees him as the bad guy.
Darth Vader could be a great main antagonist. His power in the Force and his imposing presence would be a huge threat to The Flash. He could try to capture The Flash to study his speed abilities for the Empire.
A powerful wizard who wants to harness Bella's destructive power for his own evil purposes could be the main antagonist.
It could be a rogue ninja who has also harnessed the power of a god of destruction. This ninja wants to use the power to rule the ninja world and Naruto has to stop him.
Darth Maul could be a great antagonist. His double - bladed lightsaber would be a formidable weapon against Naruto. Maul's acrobatic fighting style and his Sith powers would pose a huge challenge to Naruto's ninja skills and new - found Jedi powers.
One interesting plot idea could be exploring the backstory of a minor character from the original Star Wars universe and how they are drawn into a path of destruction. Maybe a young mechanic on a remote planet who gets caught up in a Sith plot.
The main antagonist could be a rogue Imperial officer who has his own agenda. He's tired of following the Emperor's orders and decides to create his own power base. He targets Delta Squad because they keep getting in the way of his plans to steal valuable resources and technology from various planets.
The main antagonist could be a powerful Sith Lord. This Sith Lord might see the rogue knight as a threat to their plans for galactic domination. Since the rogue knight is operating outside the normal Jedi - Sith conflict, the Sith Lord would want to eliminate this unpredictable element.
Obviously, the Titan of Destruction would be the main antagonist. It could be a powerful and terrifying figure, with abilities that can cause mass destruction. It might have a horde of minions that Percy and his friends have to fight through.